There has heretofore been proposed a plastic bag including panel portions, side gusset portions and a bottom gusset portion, as disclosed in U.S. Pat. No. 7,331,917. The panel portions are formed by two sheets of panel material which are opposed to each other. The side gusset portions are formed by two sheets of side gusset material which are interposed between the sheets of panel material to extend along the opposite side edges of panel portions. The bottom gusset portion is formed by a sheet of bottom gusset material which is interposed between the sheets of panel material to extend along ones of the opposite end edges of panel portions. The plastic bag can therefore be enlarged by the side gusset portions to obtain an increased capacity. A flat bottom surface can be formed by the bottom gusset portion to make the plastic bag stand stably.
In addition to the side gusset portions and the bottom gusset portion, an additional bottom gusset portion may be formed by a sheet of additional bottom gusset material which is interposed between the webs of panel material to extend along the other end edges of panel portions, as disclosed in Japanese Patent Publication No. 4,108,846. In this case, the plastic bag can be shaped into a rectangular parallelepiped to have an appearance of box when being filled with content. A flat top surface is formed by the bottom gusset portion while a flat bottom surface is formed by the additional bottom gusset portion. The plastic bag is therefore high in efficiency of being filled. The plastic bags can be piled up conveniently.
The plastic bag of the U.S. patent or the Japanese Patent is therefore expected to be used widely in the future. In this connection, it is required to make the plastic bag have an added value. For example, the plastic bag is too heavy to carry it when being large and being filled with content. It is therefore required to make the plastic bag provided with a handle hole in position to carry the plastic bag by the handle hole.
It is also required to make the plastic bag provided with a zipper in position to open and close the plastic bag by the zipper. It is also required to make the plastic bag provided with an opening in position. It is also required to make the plastic bag provided with adhesive means to close the plastic bag.
It is therefore an object of the invention to provide a new and improved apparatus for successively making plastic bags each of which includes panel portions, side gusset portions and a bottom gusset portion.
Other object is to make the plastic bag have an added value.